Bromine atoms usually end up with SEVEN valence electrons.
Bromine belongs to group 17 i.e. halogen group. Its atomic number is 35. The electron configuration of Bromine is 1s² 2s²2p⁶ 3s²3p⁶ 4s²3d¹⁰4p⁵. In the last shell, we see 4s²4p⁵, thus 2+5 = 7 valence electrons are present.
Some colours appear as white
1) An endothermic reaction is a reaction where heat is "absorbed" and the surrounding area is cooled. An example of an endothermic reaction is the classic baking soda and vinegar reaction. The mixture gets cold.
An exothermic reaction is one which gives off heat, such as burning, which is itself a chemical reaction.
2) (I don't actually know this one but i hope i helped with number one)
Cool liquid from 314 K to 273 K, freeze liquid at 273 K, and cool solid to 263 K.
